In all electronic appliances efforts are made to reduce power consumption, in particular when the appliance is, in what is known as a stand-by mode. Stand-by mode is a mode in which the appliance is off, except a receiving circuit which is to receive an infrared reset signal, for instance, from a remote control box.
In the case of a VCR which is permanently connected to a decoder and a TV, the TV may be ON while the VCR and the decoder are in a stand-by mode. This state last as long as the user does not switch to a channel in which the video signal is transmitted in a scrambled way. If the user switches to a scrambled channel then the decoder has to be turned ON. The change to be made at the level of the decoder transit through the VCR, the VCR being in stand-by mode. More precisely, The video signal from the TV enters the VCR via a first pin of a first connection generally known as scart 1 which is at the rear of the VCR, and leaves the VCR toward the decoder, via a first pin of a second connection known as scart 2 which is also at the rear of the VCR. The decoder will detect whether the received signal is a scrambled signal. If the received signal is detected to be a scrambled one, a microprocessor in the decoder will set a second pin of scart 2 to high. A microprocessor in the VCR which has a routine to check the level of the second pin of scart 2, will receive the information. When the second pin is detected high, the routine will set a second pin of scart 1 to high. The unscrambled video signal from the decoder re-enters the VCR via a third pin of scart 2 and leaves the VCR via a third pin of scart 1 back to the TV. This signal loop from TV to decoder via VCR is made possible by switches of the VCR which are under the control of the microprocessor in the VCR.
The purpose of the invention is to reduce the power consumption of the VCR, while the VCR is in stand-by mode and connected via its scarts 1 and 2 to a decoder (or any other devices which have scart connection) and to a TV receiver.